You may one day find yourself 5 years in on a job. Having rebuilt the infrastructure from a total mess to a well oiled machine. It's great to have pride in your work, but the infrastructure is owned by the company. You don't owe it anything, and need to be ready to let it go if greener pastures come along.
Don't get possessive either. Avoid using pronouns such as my or mine to describe a tech stack. You may find yourself needing to share your workload, and your instinct will tell you to protect your baby from the outsider, but that instinct is WRONG!